JP2571220B2 - Cigarette filter and cigarette with filter attached thereto - Google Patents

Description

The present invention relates to an aerated filter for cigarettes, comprising a first core member and a second core member which are arranged in the longitudinal direction of the filter and are in contact with or separated from each other, and Air permeable that extends along the entire circumference or a part of the circumference of the first core member and the second core member and provides ventilation of the filter in a region separated from the first core member in a longitudinal direction of the filter; Wrap (cover), the first
Of the filter is air permeable in the longitudinal direction of the filter, but is substantially air impermeable in the radial direction of the filter over its entire cross section, and all of the filter cross section in the air permeable wrap is Occupying, the second core member being air permeable in the longitudinal and radial directions of the filter, and the longitudinal pressure drop of the filter of the first core member being reduced by the filter of the second core member. A generally cylindrical cigarette filter characterized by a pressure drop in the longitudinal direction that is higher than the longitudinal pressure drop. The first and second core members may be in contact or separated in a longitudinal direction, and ventilation may enter the second member radially air permeable, for example, and / or the first may be radially permeable. And the second core member. The cover may be a complete cover made of a porous or porous material having a substantially uniform air permeability over its length. Alternatively, it may be a partial covering consisting of one or more sections, all or each of which extends only partially around the core of the filter, whereby between the longitudinal ends of the section A gap is formed that extends the length of the filter and allows unrestricted ventilation therein.

The first core member is preferably radially opaque over its entire cross section. It is preferably integral except for any outer cover forming part of it. It is preferably substantially uniform over its entire cross section. It preferably occupies the entire cross-section of the filter completely and unobstructed (except for the part occupied by a common or partial cover). Therefore the first
The core member preferably consists of a single, substantially uniform plug of annular cross section which may include its own cover.

In a filtered cigarette, the filter according to the invention usually has a high pressure drop core member directed toward the tobacco rod and a vent into the filter downstream of the high pressure drop member. Incorporated towards. The filter is usually incorporated into the filtered cigarette by a venting overwrap generally having a vent hole located downstream of the high pressure drop core. The ventilation overlay may be a common cover for the first and second core members described above, but more generally these core members have a common cover. It is preformed into the subassembly, which is then incorporated into the filtered cigarette by the venting overlay. The subassembly is preferably manufactured continuously, with the continuous rod-shaped body being cut to a determined length when it is manufactured, these determined lengths generally being the last individual Generally two cigarettes, which are multiples of the length of the filter and in the manufacture of filtered cigarettes a double-length rod is attached thereto by a double-length covering overwrap. The assembly is then cut lengthwise between the rod-shaped bodies of the same, and then the assembly is cut in the middle to form two filtered cigarettes.

A variety of structures and materials can be used for high pressure drop core members. Wrinkles are formed in the longitudinal direction without substantial fibrillation to maintain air impermeability, and are collected in the lateral direction and are permeable in the longitudinal direction along the wrinkles. It is presently preferred to use a plastic film that forms a filter plug that is substantially impermeable in the radial direction. The collected corrugated film may be bonded to itself to provide a self-supporting dimensionally stable rod or plug, but is more commonly maintained in a rod form by a wrapper. The plastic film is preferably polyethylene.

The low pressure drop core can be in conventional form, such as collected cellulose acetate fibrous tow or collected porous crepe paper. It is preferable that the core member is a single body. The core member may be radially air permeable. Preferably, it is substantially uniform over its entire cross section. The core member can completely and continuously occupy the entire cross section of the filter (other than the portion occupied by any cover). Therefore, the second core member is preferably made of a single, substantially uniform plug having an annular cross section.

Preferably, each of the first and second core members and the filter as a whole has a low inherent mechanical retention. In particular, in the filter and filter cigarette of the present invention, the percentage of air dilution as it passes through the filter is the percentage of retention of the filter "impermeable" or "closed" tar, i.e., air passing through the filter. Preferably, it is greater than that measured for an equivalent filter or cigarette that was prevented from being diluted with. The percentage of air dilution referred to herein is the percentage by volume of ventilation air added through the filter in the total mixture transmitted by the filter, and therefore 50% ventilation or air dilution is each one A 50/50 volume ratio of added air and original smoke during blowing means a 40% air dilution means a 40/60 ratio, and so on.

The present invention relies on the relative properties (in combination with the degree and location of ventilation) of the first and second core members, rather than the absolute values of the properties. However, on the one hand, while this is by no means essential for filters made in accordance with the present invention, the first wick is generally closed pressure drop (i.e., measured without aeration) above 50 mm water gauge pressure (Wg). The second core member is 50 mm
Has a closing pressure drop of less than Wg. The closing pressure drop for a given mold (composition, structure, packing density, etc.) of the first core member is proportional to the length, and the same is applicable to the second core member. The closing pressure drop is substantially additive, so that the desired closing pressure drop of the filter can be easily achieved. For a second core in the form of a conventional filter stopper (eg, collected cellulose acetate tow), the change in closed tar retention and closed pressure drop is generally substantially linear, with a ratio of 1 It is generally preferred that they be larger and have a closed tar retention of less than 30%.

For the first core member, it is preferred that the change in the closed tar retention and the closing pressure drop is substantially smaller,
It is generally preferred that the closed tar retention be less than 20%. The closed tar retention of the filter is preferably 40%
Is less than.

Filters according to the present invention, on the one hand, do not allow unacceptably low levels of filtered cigarette flavor and pressure drop and, on the other hand, allow very high air dilution (eg 50% or 60% or more). that's all)
The generally incompatible goal of good CO reduction can be achieved. While various conventional filter constructions aimed to do this, the filter of the present invention employs an upstream core having a very high pressure drop and a low retention value.
A downstream core member having a low pressure drop and a low holding value;
It can be achieved to an improved degree by using a combination of high air dilution downstream of the high pressure drop member; improved efficiency has been achieved in the past with a substantially uniform cross-section for this purpose in the past. Can be obtained by a filter without the use of implant materials or capillaries which would be blocked and reduce efficiency; the entire cross section of the filter could be used, and the filter could be of conventional shape And present even the last dirt between the cigarettes; moreover, in view of the very high pressure drop that can be provided by the first (upstream) core member, a relatively small vent is sufficient. The desired high air dilution level can be obtained relatively easily without the need to use extremely porous tips; small vents and high upstream pressure drops Combined is seen, it is possible to reduce the amount or prevents the smoke escaping through the vent hole during the puff and puff, the latter is an undesirable phenomenon frequently encountered in conventional breathable filter.

The present invention is further described by the following actual data and examples associated with the accompanying drawings.

The following Table 1 shows the closure of a number of first core members suitable for use in the present invention when used alone on a standard king size cigarette rod body of the same British country. The pressure drop (PD) is shown together with the closed tar retention (TR) of these components. In each case, the first core member consists of a non-fibrillated polyethylene film collected in a rod-like form having a plug with a corrugated wrinkle formed in the longitudinal direction and a cover on the outside, Different pressure drops for plugs of the same length reflect differences in packing density of the collected film from plug to plug.

Table 1 Length of the first core member PD (mmWg)% TR 6mm 75 11.5 6mm 94 12.5 8mm 85 13.9 10mm 143 17.5 10mm 169 16.5 10mm 212 16.5 15mm 208 21.0 FIG. 1 of the accompanying drawings is suitable for the present invention. The first used
And a graph showing a change in a closed tar retention (TR) of the second core member with respect to a closing pressure drop (PD). Line A plats the closed tar retention of a first core member (of the type described above in connection with Table 1) of different lengths but otherwise substantially identical against a closed pressure drop. It is obtained. Line B is similarly obtained for a second core member having a different length but otherwise identical in 8-filament denier cellulose acetate tow (fiber denier of 8) each in the form of a collected and bonded plug. It was done. The length of the second core member was varied from 10 to 35 mm, and the length of the first core element was varied from 6 to 15 mm. It can be seen that the tar retention of the first core is relatively insensitive to pressure drops, and therefore the first and second cores are suitably selected and the desired degree downstream of the first core is provided. The predetermined and improved filter efficiency described above is easily achieved.

The efficiency characteristics of the filter and the cigarette with the filter according to the invention are illustrated by the figures quoted in Tables 2 and 3 below. Table 2 shows two filters according to the invention, each having a length of 20 and 25 mm and a circumference of about 25 mm, when each filter was used in connection with a standard king size cigarette rod body of the United Kingdom. Shows the filter closing pressure drop (mm water pressure) and closed tar retention% of the filter,
And these values of each core member are also given. Table 3
Compares these two filters mounted on two commercially available brands of the same sized conventional "monoacetate" filter cigarette. In each case, the filter of the present invention was mounted on the same cigarette rod body used in comparison with the above commercially available ones. In each case, the traditional “monoacetate”
The filter is a collected bundle of cellulose acetate fiber tow. Each of the filters according to the present invention is collected and coupled to a first upstream plug of polyethylene film collected in a longitudinally wrinkled, non-fibrillated rod having an outer cover. 8/40 cellulose acetate tow (filament denier 8, total denier 40
× 1000) adjacent uncovered downstream plugs and a common air permeable plug cover. In a filter according to the invention having a length of 25 mm, the upstream plug (of the corrugated wrinkled polyethylene film) is 10 mm in length,
The plug on the downstream side of the bonded cellulose acetate fiber tow is 15 mm in length, and in the filter according to the present invention having a length of 20 mm, the plug on the upstream side of the corrugated wrinkled polyethylene film has a length of 6 mm. The plug on the downstream side of the bonded cellulose acetate fiber tow is 14 mm long. The filter is mounted on the rod-shaped body of tobacco by covering in each case the tip of the ventilation hole of the overlap, which is also located on the second core member in the filter according to the invention.

Unless otherwise specified, all measurements quoted here are obtained by accepted procedures recommended by CORESTA (Cooperation Center for Interdisciplinary Scientific Research on Tobacco).

Filters according to the present invention can provide improvements that reduce not only CO but also other vapor phase components such as HCN and formamide, and provide better vapor phase / tar reduction ratios than conventional filters.

As with conventional large aeration and low retention filters, incorporating an adsorbent (eg, activated carbon) for further vapor phase reduction in the filter according to the invention (eg, separate first and second filters). Between two core members)
It will also be very easy.

FIGS. 2 and 3 of the accompanying drawings illustrate the 20 mm long filters according to the invention of Tables 2 and 3.
The filter comprises an upstream first core member (2) in a common air-permeable plug cover (6) and a downstream second core member (4) adjacent thereto. This sub-assembly is mounted by covering an wrapped tobacco rod-shaped main body (8) with an overlap portion (10) having an annular portion (12) which is a ventilation hole of a core member (4). . As shown in FIG. 3, the upstream first core member (2) is completely and unobstructed across the entire cross-section of the filter in the common cover (6) (i. A single, substantially uniform plug (14) in a cover (16) that extends over a path (without large internal detours). As indicated earlier, the core member (4) can be located remotely downstream of the core member (2), in which case the ventilation holes are preferably provided in the space between the two core members. Become.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the first filter used in the filter according to the invention.
9 is a graph illustrating the properties of a second core member. FIG. 2 is a schematic longitudinal sectional view of a filter according to the present invention incorporated in a cigarette with a filter. FIG. 3 is a sectional view taken along line III-III of FIG. DESCRIPTION OF SYMBOLS 1 ... 1st core member, 4 ... 2nd core member 6 ... Plug cover body, 8 ... Bar-shaped main body 10 ... Overlap part, 12 ... Annular part 14 ... Plug body, 16 ... Cover body

Claims (7)

(57) [Claims] 1. A cigarette filter comprising a first core member, a second core member, and an air-permeable wrap, wherein the first core member is on the tobacco rod side and the second core member is The first core member and the second core member are arranged in the longitudinal direction of the filter so as to be on the suction side, and the wrap is arranged in the longitudinal direction of the filter along the periphery of the first core member and the second core member. Extend to completely cover the periphery of the member or to cover a portion of the filter in the circumferential direction, and to provide air permeability from the outside of the filter to the inside of the filter in a region of the filter other than the first core member. The first core member is air and smoke permeable in the longitudinal direction of the filter, but is substantially air and smoke permeable in the radial direction of the filter over its entire cross section, and the air permeable In the lap Occupies all of the Luther cross section, so that air cannot enter the filter in the region of the first core member, and air enters the filter in regions other than the first core member, The second wick is air and smoke permeable in the longitudinal and radial directions of the filter, and the suction resistance of the first wick in the longitudinal direction of the filter is greater than the suction resistance of the second wick. A cigarette filter characterized by being expensive. 2. The filter according to claim 1, wherein said first core member and said second core member are in contact with each other. 3. The filter according to claim 1, wherein the first core member and the second core member are separated from each other in a longitudinal direction of the filter, and a space exists between the first core member and the second core member. The filter according to 1. 4. The filter according to claim 1, wherein said first core member is substantially uniform over its entire cross section. 5. The filter according to claim 1, wherein said second core member is substantially uniform over its entire cross section. 6. The filter according to claim 1, wherein the first core member is formed with a wavy wrinkle in the longitudinal direction of the filter without fibrillation.
The filter according to any one of claims 1 to 5, wherein the filter is made of a plastic film that is air-permeable in the longitudinal direction but air-impermeable in the radial direction, and is integrated in the radial direction of the filter. 7. A cigarette filter comprising a first core member, a second core member, and an air-permeable wrap, wherein the first core member is on the tobacco rod side and the second core member is. The first core member and the second core member are arranged in the longitudinal direction of the filter so as to be on the suction side, and the wrap is arranged in the longitudinal direction of the filter along the periphery of the first core member and the second core member. Extend to completely cover the periphery of the member or to cover a portion of the filter in the circumferential direction, and to provide air permeability from the outside of the filter to the inside of the filter in a region of the filter other than the first core member. The first core member is air and smoke permeable in the longitudinal direction of the filter, but is substantially air and smoke permeable in the radial direction of the filter over its entire cross section, and the air permeable In the lap Occupies all of the Luther cross section, so that air cannot enter the filter in the region of the first core member, and air enters the filter in regions other than the first core member, The second wick is air and smoke permeable in the longitudinal and radial directions of the filter, and the suction resistance of the first wick in the longitudinal direction of the filter is greater than the suction resistance of the second wick. A cigarette filter characterized by being high, the first core member is incorporated in the direction of the rod-shaped main body of the cigarette, and the second core member downstream of the first core member is incorporated with the suction side, and the first core member is incorporated. A tobacco with a filter that vents into the filter downstream of the core member.